Some curious thing about tmpgenc
 

Hello,
I've been doing some tests with tmpgenc latelly and I've come up with something very strange.
At the time, I'm comparing tmpgenc 2.254.63.181 with Peter Cheat's NuEnc 0.01b.
All my tests are based on MPEG-1 encoding.
Here's the strange issue.
When comparing tmpgenc/nuenc's frames I noticed some very weird image shrinking in tmpgenc.
Here's the script I used on both encoders:
Accoring to the Letterbox I'm using, I am doing an overlap overscan=1, right?
Now look at some screenshots from both encoders.
TMPGEnc CQ 63.3 - Frame# 2242 - Frame type=I
http://www.digitalfaq.com/archives/i.../2004/12/3.jpg

NuEnc CQ 85 - Frame# 2242 - Frame type=B
http://www.digitalfaq.com/archives/i.../2004/12/4.jpg

Thanks to ImageShack for Free Image Hosting

Now notice that tmpg's screenshot almost makes you think that I set up the overscan=2, right?
But I didn't :!:
It's set up for overscan=1 from the script :!:
Do notice that all the frame information is really in the screenshot.
It's just as if it shrinked the image by a fraction :roll:
Now notice nuenc's screenshot.
It looks normal, and it is fractionally worse than tmpg's, I mean quality wise.
But quality comparison is not the main issue here, even because the frame types don't match up with eachother :!:
Can somebody try to replicate this, please?
Maybe I'm doing something wrong in tmpg.
BTW, I have tried several "Video arrange method"'s in tmpgenc, but they all look the same.
Here's some screenshots of my settings on both tmpgenc and nuenc:
http://www.digitalfaq.com/archives/i...2004/12/21.gif
http://www.digitalfaq.com/archives/i...2004/12/22.gif
http://www.digitalfaq.com/archives/i...2004/12/23.gif
http://www.digitalfaq.com/archives/i...2004/12/24.gif
http://www.digitalfaq.com/archives/i...2004/12/25.gif
(This one is too small to generate a thumbnail, that's why it's the original)
http://www.digitalfaq.com/archives/i...2004/12/26.gif
Hope somebody can try to replicate this and can even come up with a theory as to why tmpgenc does shrink the image.
Cheers

EDITED:
Here is a screenshot without the "shrinking" issue encoded with Video Arrange Method :arrow: Full Screen, as
per Karl's suggestion ;-)
TMPGEnc CQ 63.3 - Frame# 2242 - Frame type=I
http://www.digitalfaq.com/archives/error.gif
Please click on the thumbnails to see larger images.
And once again, Thanks to ImageShack for Free Image Hosting.
Cheers

a long time ago, before the wheel discovery i post about it but only get discussions( i was elected as st.., idi...and some more "cool" synonymous and people with strees to answer),then forget my opinion(maybe in portuguese i can told for you) but in one hint i "insist":
post the links and right vlick to open a new page for each picture,is easy to compare:

http://img70.exs.cx/img70/2057/x2tmpg2242i1kd.jpg

http://img62.exs.cx/img62/5176/x2nuenc2242b3cp.jpg

:!:

ps:
Correia, i'm talking with you and to myself:
why people delay months to see what i saw first? :? (poor english to write?...!)
search (if you have time/patience)and you will find exact what you're showing! 8O

Re: Some curious thing about tmpgenc
 

Hi Rui,

Set "Full Screen" in TMPEG under "Video arrange method". Not :arrow: Full Screen (Keep Aspect) :)
That's why TMPEG cut off some edges ;)

-kwag

@Karl
Damn I am sure I have already tried that.
But I'm testing again.
Thanks for the tip.
I'll post the results in some minutes.
@Jeo
Thanks for the tip about the links.
But I'm affraid as soon as I figure out what's going on, I'll post the thumbs instead.
As for the poor English, forget it: there's no problems understanding you buddy.
Cheers

@Karl
Ok, It was down to the Video Arrange Method :D.
I would swear I had already tried Full Screen before without curing it, but apparently I didn't.
I was almost believing tmpgenc had some problem :lol:.
BTW, I thought this VAM had something to do with the SAP.
Some SAP's would like Center better than Full Screen and some otherwise.
What about those other options that say "keep aspect ratio" and "keep aspect ratio 2"?
In which cases should they be used?
Does it have any influence the target your aiming KSVCD/KDVD and the VAM you choose?
I don't think so, but I'd be glad to be 100% sure.
Could you enlighten me on this matter?
Now that I come to think of it: I've done several KDVD using Center (keep aspect ratio).
Should I reencode those in FS?
Thanks for the tips.
Cheers

:lol: If you are using an AviSynth script, using "Center" of "Full Screen" is the same thing. Under some rare conditions, and when you are NOT using AviSynth, only :!: Yes, because it will affect final aspect ratio and size. Yep. You shure should :)
Either "Center" or "Full Screen", but no "X_(keep aspect)" option.

-kwag

Yes indeed.
It seems that I only tested x_(keep aspect) VAM options :evil: .
Shame on me :(
Ok, since I'll only be using AVS as source, I'll be fine with Center/FS ;-)
Damn, damn, damn!
And you don't believe me when I tell you I am still a big noob :evil: :?:
Now, I'll have to reencode them all over again, grrrr :lol:
Thankfully, I put a label on everyone of them with the settings used, phew.
It won't be hard to locate them and reencode them :lol:
I've edited my 1st post to reflect the answer you guy gave me.
Thanks for all the tips.
Cheers all

The good thing about that is that now you'll make them better :rotf:
The more we encode, the better we get at it :hihi:

-kwag

Re: Some curious thing about tmpgenc
 

here we go again:..... :roll: :lol: :lol:

http://img70.exs.cx/img70/2057/x2tmpg2242i1kd.jpg

http://img62.exs.cx/img62/5176/x2nuenc2242b3cp.jpg

http://img137.exs.cx/img137/8342/x2tmpg2242igood5hi.jpg

you see differences between pictures 2 and 3 ?

Re: Some curious thing about tmpgenc
 

There is no difference at all (aspect wise, I mean), if TMPEG is set to "Full Screen", and then the same script is used for TMPEG and NuEnc.
The result is identical.

-kwag

Re: Some curious thing about tmpgenc
 

(of course, about aspect wise) :wink:
i still see less details in the very bottom (thin bright line) of tmpgenc picture!(but is irrelevant)

edited:
Correia, is possible a picture from the source?

Re: Some curious thing about tmpgenc
 

Yes, it's not relevant, because Rui was not talking about details.
His post was about the aspect ratio, and it was because he was using "Keep Aspect" on TMPEG.
Yes, I do see differences in details, but that was not Rui's issue :)

-kwag

Re: Some curious thing about tmpgenc
 

All is possible, Jeo.
Here's the original frame:
http://www.digitalfaq.com/archives/error.gif
BTW, I've talked with the Admins in private, regarding the "thumbnails/links to full screen images", and we have agreed to keep the thumbnails instead of the links.
It's not because we are not entitled to use the links, but more because it is much better for the future of Imageshack as they will have much more registered users ;-)

Yes Karl, you're right on it.
My goal was not picture details.
My goal was simply about Aspect Resolution coming from Tmpgenc.
Jeo, as we know, has a very good "eye" for picture quality.
I'll release a picture from the source so that he can take a look at it, quality wise.

@Mods
Please, split this thread from this post on.
It will have a more quality-wise approach from this point on.
And since I'm comparing NuEnc(libav) with Tmpgenc, I would think that the most appropriate place to drop it is the Freenc/Nuenc forum ;-).
Cheers

EDITED:
Post splitted here
http://www.kvcd.net/forum/viewtopic....hlight=#114108

Re: Some curious thing about tmpgenc
 

On all your examples it's clear that the # of the frame reported by the encoders and the original one is not the same. See your #1884

Damn.
You're right Phil.
Let me check what's happening with VDubMod.
TIA

Re: Some curious thing about tmpgenc
 

Could it be because you have "Output YUV data as Basic YCbCr not CCIR601" option "checked" :?:

-kwag

Re: Some curious thing about tmpgenc
 

Nope.
Karl, just checked it and it's disabled.
I'll get back to split this message myself.
Half will go to the NuEncs forum and the other half will stay here.
Stay tunned.
Cheers :D

Ok guys.
Unfortunately I had to split the post to the NuEncs forum because it didn't have much more to do with Tmpgenc anymore.
It's now about NuEnc's output quality.
But the mistery of the "dark" frames remain :roll:.
Here is a set of comparison frames.
Original:
http://www.digitalfaq.com/archives/error.gif
NuEnc's:
http://www.digitalfaq.com/archives/error.gif
Tmpg's:
http://www.digitalfaq.com/archives/error.gif
Thanks to ImageShack for Free Image Hosting
A penny for your thoughts :mrgreen:
Cheers

Can you add a "Limiter()" at the end of your script and do the comparison again ?

Else the problem can comes from internal RGB convertion (let me remind you that tmpgenc works in RGB24 and not RGB32 -> lost of luma here ? :idea:)

Will do.
I'll let you know after I run the test.
Godd thinking, btw.
Cheers